Boeing considered but never developed widebody trijet versions of its iconic jetliners

The Boeing 777 also has roots connected to trijet concepts. Initially envisioned as a competitor to existing trijets during its development phase in the 1970s, Boeing later decided to prioritize twinjet designs instead. In response to airline feedback during the late 1980s—when DC-10s and L-1011s were being phased out—the company opted for a new widebody design that became known as the Boeing 777. Certified by both U.S. and European authorities in April 1995, it entered service with United Airlines shortly thereafter on transatlantic routes.

Although initial plans for both a trijet variant of the Boeing 747 and an entirely new trijet (later called "777") did not move forward beyond early development stages or proposals due to technical or regulatory challenges—including concerns related to Extended-Range Twin-Engine Operational Performance Standards (ETOPS)—these ideas reflected ongoing efforts by manufacturers like Boeing to adapt aircraft design based on market needs and technological advances.

Other manufacturers successfully produced trijet airliners during this period: McDonnell Douglas delivered nearly four hundred DC-10 aircraft between 1969 and 1989; Lockheed built over two hundred fifty L-1011 TriStars from the late sixties through mid-eighties.

As engine technology improved through subsequent decades—and ETOPS regulations were relaxed—twin-engine jets became capable of flying longer distances previously reserved for three or four-engined planes. This shift led airlines to favor models like Boeing's own twinjet offerings due to lower operating costs and greater flexibility.

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